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Protein Structures and Oligomeric States

Enter a protein name, UniProt accession or PDB ID. Name searches ask you to confirm the protein identity before related structures are queried.

Current Protein Identity：O88703 New Search
15PDB entries
25Biological assembly
36chain/assembly records
Main Difference Dimensions in This Set
Different construct Different mutation/modification Different assembly state Different ligand/ion Different experimental method Different experimental conditions Different structure-quality metrics

Difference tags compare only the current result set; every original PDB and assembly record remains separate.

Related-Structure Differences

Each row represents one biological assembly in one PDB entry; multiple monomers of the same protein are listed separately.

PDB Entry Assembly / Oligomeric State Construct Mutations and Modifications Ligands, Ions and Non-polymers Experimental Method Experimental Conditions Structure Quality
1Q3E HCN2J 443-645 in the presence of cGMP Deposited 2003-07-29 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–645（203 aa） Fragment：Residues 443-645 (Reference sequence numbering)
Not recorded PCG CYCLIC GUANOSINE MONOPHOSPHATE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；PEG 400, sodium citrate, sodium chloride, DTT, HEPES, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 1.90 Å R-free 0.239
1Q3E HCN2J 443-645 in the presence of cGMP Deposited 2003-07-29 Assembly 2 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain B 443–645（203 aa） Fragment：Residues 443-645 (Reference sequence numbering)
Not recorded PCG CYCLIC GUANOSINE MONOPHOSPHATE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；PEG 400, sodium citrate, sodium chloride, DTT, HEPES, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 1.90 Å R-free 0.239
1Q3E HCN2J 443-645 in the presence of cGMP Deposited 2003-07-29 Assembly 3 Protein homooligomer Homooligomer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain A 443–645（203 aa） Fragment：Residues 443-645 (Reference sequence numbering)
Chain B 443–645（203 aa） Fragment：Residues 443-645 (Reference sequence numbering)
Not recorded PCG CYCLIC GUANOSINE MONOPHOSPHATE × 8 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；PEG 400, sodium citrate, sodium chloride, DTT, HEPES, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 1.90 Å R-free 0.239
1Q43 HCN2I 443-640 in the presence of cAMP, selenomethionine derivative Deposited 2003-08-01 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–645（203 aa） Fragment：residues 443-645
Non-standard monomer：Yes (specific site not provided by mmCIF) CMP ADENOSINE-3',5'-CYCLIC-MONOPHOSPHATE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；PEG 400, sodium citrate, sodium chloride, DTT, HEPES, cAMP, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.00 Å R-free 0.242
1Q43 HCN2I 443-640 in the presence of cAMP, selenomethionine derivative Deposited 2003-08-01 Assembly 2 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain B 443–645（203 aa） Fragment：residues 443-645
Non-standard monomer：Yes (specific site not provided by mmCIF) CMP ADENOSINE-3',5'-CYCLIC-MONOPHOSPHATE × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；PEG 400, sodium citrate, sodium chloride, DTT, HEPES, cAMP, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.00 Å R-free 0.242
1Q43 HCN2I 443-640 in the presence of cAMP, selenomethionine derivative Deposited 2003-08-01 Assembly 3 Protein homooligomer Homooligomer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain A 443–645（203 aa） Fragment：residues 443-645
Chain B 443–645（203 aa） Fragment：residues 443-645
Non-standard monomer：Yes (specific site not provided by mmCIF) Non-standard monomer：Yes (specific site not provided by mmCIF) CMP ADENOSINE-3',5'-CYCLIC-MONOPHOSPHATE × 8 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；PEG 400, sodium citrate, sodium chloride, DTT, HEPES, cAMP, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.00 Å R-free 0.242
1Q43 HCN2I 443-640 in the presence of cAMP, selenomethionine derivative Deposited 2003-08-01 Assembly 4 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain B 443–645（203 aa） Fragment：residues 443-645
Non-standard monomer：Yes (specific site not provided by mmCIF) CMP ADENOSINE-3',5'-CYCLIC-MONOPHOSPHATE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；PEG 400, sodium citrate, sodium chloride, DTT, HEPES, cAMP, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.00 Å R-free 0.242
1Q5O HCN2J 443-645 in the presence of cAMP, selenomethionine derivative Deposited 2003-08-08 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–645（203 aa） Fragment：Residues 443-645
Non-standard monomer：Yes (specific site not provided by mmCIF) CMP ADENOSINE-3',5'-CYCLIC-MONOPHOSPHATE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；PEG 400, sodium citrate, sodium chloride, DTT, HEPES, cAMP, pH 4.6, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.30 Å R-free 0.261
2Q0A Structure and rearrangements in the carboxy-terminal region of SpIH channels Deposited 2007-05-21 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–640（198 aa） Fragment：C-TERMINAL DOMAIN (residues 443-640)
Mutation：I636D PCG CYCLIC GUANOSINE MONOPHOSPHATE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 5；277 K；10 % w/v PEG 8000, 0.5 M NaCl, 15 % Glycerol, 0.1 M MES, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.25 Å R-free 0.261
2Q0A Structure and rearrangements in the carboxy-terminal region of SpIH channels Deposited 2007-05-21 Assembly 2 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain B 443–640（198 aa） Fragment：C-TERMINAL DOMAIN (residues 443-640)
Mutation：I636D PCG CYCLIC GUANOSINE MONOPHOSPHATE × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 5；277 K；10 % w/v PEG 8000, 0.5 M NaCl, 15 % Glycerol, 0.1 M MES, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.25 Å R-free 0.261
2Q0A Structure and rearrangements in the carboxy-terminal region of SpIH channels Deposited 2007-05-21 Assembly 3 Protein homooligomer Homooligomer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain A 443–640（198 aa） Fragment：C-TERMINAL DOMAIN (residues 443-640)
Chain B 443–640（198 aa） Fragment：C-TERMINAL DOMAIN (residues 443-640)
Mutation：I636D Mutation：I636D PCG CYCLIC GUANOSINE MONOPHOSPHATE × 8 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 5；277 K；10 % w/v PEG 8000, 0.5 M NaCl, 15 % Glycerol, 0.1 M MES, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.25 Å R-free 0.261
2Q0A Structure and rearrangements in the carboxy-terminal region of SpIH channels Deposited 2007-05-21 Assembly 4 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain B 443–640（198 aa） Fragment：C-TERMINAL DOMAIN (residues 443-640)
Mutation：I636D PCG CYCLIC GUANOSINE MONOPHOSPHATE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 5；277 K；10 % w/v PEG 8000, 0.5 M NaCl, 15 % Glycerol, 0.1 M MES, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.25 Å R-free 0.261
3BPZ HCN2-I 443-460 E502K in the presence of cAMP Deposited 2007-12-19 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–640（198 aa） Fragment：ligand biding domain (residues 443-640)
Chain B 443–640（198 aa） Fragment：ligand biding domain (residues 443-640)
Chain C 443–640（198 aa） Fragment：ligand biding domain (residues 443-640)
Chain D 443–640（198 aa） Fragment：ligand biding domain (residues 443-640)
Mutation：E502K Mutation：E502K Mutation：E502K Mutation：E502K CMP ADENOSINE-3',5'-CYCLIC-MONOPHOSPHATE × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION；pH 4.6；279 K；PEG 400, SODIUM CITRATE, SODIUM CHLORIDE, DTT, HEPES, 5 mM CAMP, pH 4.6, VAPOR DIFFUSION, temperature 279K
Resolution 1.65 Å R-free 0.216
3ETQ X-ray structure of cysteine-free fragment of mHCN2 C-terminal region from amino acids 443-630 including C508N, C584S, and C601S mutations Deposited 2008-10-08 Assembly 1 Protein homooligomer Homooligomer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain A 443–640（198 aa） Fragment：C-terminal fragment
Chain B 443–640（198 aa） Fragment：C-terminal fragment
Mutation：C508N, C584S, C601S Mutation：C508N, C584S, C601S CMP ADENOSINE-3',5'-CYCLIC-MONOPHOSPHATE × 8 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 5；277 K；16% w/v PEG 6000, 500 mM NaCl, 10% glycerol, 100 mM citrate, pH 5.0, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 1.90 Å R-free 0.216
3FFQ HCN2I 443-640 apo-state Deposited 2008-12-04 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–640（198 aa）
Not recorded BR BROMIDE ION × 20 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；277 K；Two uL protein (5-7 mg/mL) mixed with one uL reservoir solution composed of 0.4 M NaCl, 0.1 NaBr, 0.1 M MES, pH 6.0, 20% glycerol (v/v), and 20% PEG 8000 (w/v). Crystals grew within eight weeks and harvested an additional eight weeks after initial growth, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.40 Å R-free 0.283
3FFQ HCN2I 443-640 apo-state Deposited 2008-12-04 Assembly 2 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain B 443–640（198 aa）
Not recorded BR BROMIDE ION × 16 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；277 K；Two uL protein (5-7 mg/mL) mixed with one uL reservoir solution composed of 0.4 M NaCl, 0.1 NaBr, 0.1 M MES, pH 6.0, 20% glycerol (v/v), and 20% PEG 8000 (w/v). Crystals grew within eight weeks and harvested an additional eight weeks after initial growth, VAPOR DIFFUSION, HANGING DROP, temperature 277K
Resolution 2.40 Å R-free 0.283
4EQF Trip8b-1a#206-567 interacting with the carboxy-terminal seven residues of HCN2 Deposited 2012-04-18 Assembly 1 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain B 857–863（7 aa） Fragment：UNP residues 857-863
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；pH 6；298 K；91mM MES, 91mM triSodium citrate, 3.63M NaCL, VAPOR DIFFUSION, SITTING DROP, temperature 298K
Resolution 3.00 Å R-free 0.281
5JON Crystal structure of the unliganded form of HCN2 CNBD Deposited 2016-05-02 Assembly 1 Insufficient information Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain A 494–640（147 aa）
Not recorded NO3 NITRATE ION × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 6；293 K；34-36% dimethyl PEG 500, 240 mM potassium nitrate, 20 mM magnesium chloride, 100 mM BIS-TRIS, pH 6.0
Resolution 2.04 Å R-free 0.221
5JON Crystal structure of the unliganded form of HCN2 CNBD Deposited 2016-05-02 Assembly 2 Insufficient information Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain B 494–640（147 aa）
Not recorded NO3 NITRATE ION × 2 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 6；293 K；34-36% dimethyl PEG 500, 240 mM potassium nitrate, 20 mM magnesium chloride, 100 mM BIS-TRIS, pH 6.0
Resolution 2.04 Å R-free 0.221
5KHG HCN2 CNBD in complex with cytidine-3', 5'-cyclic monophosphate (cCMP) Deposited 2016-06-14 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–643（201 aa） Fragment：UNP residues 443-643
Non-standard monomer：Yes (specific site not provided by mmCIF) CC7 4-amino-1-[(2S,4aR,6R,7R,7aS)-2,7-dihydroxy-2-oxidotetrahydro-4H-furo[3,2-d][1,3,2]dioxaphosphinin-6-yl]pyrimidin-2(1H)-one × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 5；277 K；200 mM NaCl, 0.1 mM sodium citrate pH 5.0, 16% PEG 400
Resolution 2.24 Å R-free 0.264
5KHH HCN2 CNBD in complex with inosine-3', 5'-cyclic monophosphate (cIMP) Deposited 2016-06-14 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–643（201 aa） Fragment：UNP residues 443-643
Non-standard monomer：Yes (specific site not provided by mmCIF) 6SW Inosine-3',5'-cyclic monophosphate × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 5.5；277 K；200 mM NaCl, 0.1 mM sodium citrate pH 5.5, 14.5% PEG 400
Resolution 1.77 Å R-free 0.263
5KHI HCN2 CNBD in complex with purine riboside-3', 5'-cyclic monophosphate (cPuMP) Deposited 2016-06-14 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–643（201 aa） Fragment：UNP residues 443-643
Non-standard monomer：Yes (specific site not provided by mmCIF) 6SX Purine riboside-3',5'-cyclic monophosphate × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 5.5；277 K；200 mM NaCl, 0.1 mM sodium citrate pH 5.5, 18% PEG 400
Resolution 2.10 Å R-free 0.249
5KHJ HCN2 CNBD in complex with uridine-3', 5'-cyclic monophosphate (cUMP) Deposited 2016-06-14 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–643（201 aa） Fragment：UNP residues 443-643
Chain B 443–643（201 aa） Fragment：UNP residues 443-643
Not recorded 6SY Uridine-3',5'-cyclic monophosphate × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；200 mM NaCl, 0.1 mM sodium citrate pH 4.6, 13% PEG 400
Resolution 2.01 Å R-free 0.252
5KHK HCN2 CNBD in complex with 2-aminopurine riboside-3', 5'-cyclic monophosphate (2-NH2-cPuMP) Deposited 2016-06-14 Assembly 1 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 443–643（201 aa） Fragment：UNP residues 443-643
Non-standard monomer：Yes (specific site not provided by mmCIF) 6SZ 2-Aminopurine riboside-3',5'-cyclic monophosphate × 4 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 4.6；277 K；200 mM NaCl, 0.1 mM sodium citrate pH 4.6, 12% PEG 400
Resolution 2.07 Å R-free 0.261
9R1T Structure of the human chimera HCN112 hyperpolarization-activated cyclic nucleotide-gated ion channel in complex with cAMP. Deposited 2025-04-28 Assembly 1 Insufficient information Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 444–647（204 aa）
Chain B 444–647（204 aa）
Chain C 444–647（204 aa）
Chain D 444–647（204 aa）
Not recorded CMP ADENOSINE-3',5'-CYCLIC-MONOPHOSPHATE × 4 ELECTRON MICROSCOPY
cryo-EM buffer pH 8
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.34 Å

This page presents structural evidence recorded in PDB/mmCIF.“No recorded non-water small molecule” does not prove that the experimental sample was ligand-free; experimental conditions belong to the PDB experiment, while ligands and copy counts are shown for each biological assembly.